Fountain pen



FIG. 1 is a side perspective view of a fountain pen showing my new design in the closed position;

FIG. 2 is a side perspective view showing my new design in an exploded condition;

FIG. 3 is a rear elevational view;

FIG. 4 is a front elevational view;

FIG. 5 is a right side elevational view;

FIG. 6 is a left side elevational view;

FIG. 7 is a top plan view on an enlarged scale; and

FIG. 8 is a bottom plan view on an enlarged scale. 

The ornamental design for a fountain pen, as shown and described. 